Effect of Bacillus cohnii on Some Physicomechanical and Microstructural Properties of Ordinary Portland Cement
Cement-made materials face durability and sustainability challenges. This is majorly caused by the presence of cracks. Cracking affects the mechanical strength of cement-based materials. Microbiologically induced calcite precipitation (MICP) has been found to enhance compressive strength, thus enhan...
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| Format: | Article |
| Language: | English |
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Wiley
2020-01-01
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| Series: | Journal of Chemistry |
| Online Access: | http://dx.doi.org/10.1155/2020/7816079 |
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| author | Ngari Reginah Wangui Joseph Karanja Thiong’o Jackson Muthengia Wachira |
| author_facet | Ngari Reginah Wangui Joseph Karanja Thiong’o Jackson Muthengia Wachira |
| author_sort | Ngari Reginah Wangui |
| collection | DOAJ |
| description | Cement-made materials face durability and sustainability challenges. This is majorly caused by the presence of cracks. Cracking affects the mechanical strength of cement-based materials. Microbiologically induced calcite precipitation (MICP) has been found to enhance compressive strength, thus enhancing on the mechanical and durability properties of these materials. This paper presents the findings of a study conducted to investigate the effect of Bacillus cohnii on compressive strength development of OPC mortar prisms and the effect of Bacillus cohnii on cement setting time and soundness. Microbial concentration of 1.0 × 107 cells·ml−1 was used. Compressive strength tests analyses were carried out for each category of mortar prisms. Compressive strength tests were carried out on the 2nd, 7th, 14th, 28th, 56th, and 90th day of curing in distilled water and microbial solutions. All microbial mortars exhibited a greater compressive strength compared to the control with the highest observed at 90 days. Highest percentage gain in compressive strength was observed at 90 days which is 28.3%. Microstructural analysis was carried out using a scanning electron microscope (SEM) after 28 days of curing. The results indicated the presence of calcium carbonate and more calcium silicate hydrate (CSH) deposits on the bacterial mortars. The bacteria did not have an effect on cement soundness. Setting time was significantly accelerated. |
| format | Article |
| id | doaj-art-331ab426f63c481e868c74ed68dd4323 |
| institution | OA Journals |
| issn | 2090-9063 2090-9071 |
| language | English |
| publishDate | 2020-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | Journal of Chemistry |
| spelling | doaj-art-331ab426f63c481e868c74ed68dd43232025-08-20T02:24:18ZengWileyJournal of Chemistry2090-90632090-90712020-01-01202010.1155/2020/78160797816079Effect of Bacillus cohnii on Some Physicomechanical and Microstructural Properties of Ordinary Portland CementNgari Reginah Wangui0Joseph Karanja Thiong’o1Jackson Muthengia Wachira2Department of Chemistry, Kenyatta University, Nairobi, KenyaDepartment of Chemistry, Kenyatta University, Nairobi, KenyaDepartment of Physical Sciences, University of Embu, Embu, KenyaCement-made materials face durability and sustainability challenges. This is majorly caused by the presence of cracks. Cracking affects the mechanical strength of cement-based materials. Microbiologically induced calcite precipitation (MICP) has been found to enhance compressive strength, thus enhancing on the mechanical and durability properties of these materials. This paper presents the findings of a study conducted to investigate the effect of Bacillus cohnii on compressive strength development of OPC mortar prisms and the effect of Bacillus cohnii on cement setting time and soundness. Microbial concentration of 1.0 × 107 cells·ml−1 was used. Compressive strength tests analyses were carried out for each category of mortar prisms. Compressive strength tests were carried out on the 2nd, 7th, 14th, 28th, 56th, and 90th day of curing in distilled water and microbial solutions. All microbial mortars exhibited a greater compressive strength compared to the control with the highest observed at 90 days. Highest percentage gain in compressive strength was observed at 90 days which is 28.3%. Microstructural analysis was carried out using a scanning electron microscope (SEM) after 28 days of curing. The results indicated the presence of calcium carbonate and more calcium silicate hydrate (CSH) deposits on the bacterial mortars. The bacteria did not have an effect on cement soundness. Setting time was significantly accelerated.http://dx.doi.org/10.1155/2020/7816079 |
| spellingShingle | Ngari Reginah Wangui Joseph Karanja Thiong’o Jackson Muthengia Wachira Effect of Bacillus cohnii on Some Physicomechanical and Microstructural Properties of Ordinary Portland Cement Journal of Chemistry |
| title | Effect of Bacillus cohnii on Some Physicomechanical and Microstructural Properties of Ordinary Portland Cement |
| title_full | Effect of Bacillus cohnii on Some Physicomechanical and Microstructural Properties of Ordinary Portland Cement |
| title_fullStr | Effect of Bacillus cohnii on Some Physicomechanical and Microstructural Properties of Ordinary Portland Cement |
| title_full_unstemmed | Effect of Bacillus cohnii on Some Physicomechanical and Microstructural Properties of Ordinary Portland Cement |
| title_short | Effect of Bacillus cohnii on Some Physicomechanical and Microstructural Properties of Ordinary Portland Cement |
| title_sort | effect of bacillus cohnii on some physicomechanical and microstructural properties of ordinary portland cement |
| url | http://dx.doi.org/10.1155/2020/7816079 |
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